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The BAE SYSTEMS Trusted Filter is a filter for asynchronous serial data that can be used in a number of applications, primarily to provide RED/BLACK separation in systems where BLACK equipment is remotely controlled from a RED area via a serial remote control port.

The Trusted Filter provides RED/BLACK separation in systems where control data, which cannot be protected by other means, must cross a RED/BLACK boundary. This is achieved by the filtering of RED data to produce ORANGE data. The control data is in the form of arbitrary length strings of characters. The control data is in plaintext.

Data passing from RED to BLACK is filtered in accordance with a table of allowable commands. The filter ensures that only control data of a pre-defined nature are passed. Only valid control data are passed to the BLACK area. Invalid control data are discarded.

Allowable data tables are encoded in EPROM and are not modifiable in the field. There is no operator interface, except for two diagnostic LEDs.

This version uses one filter channel instead of four channels, resulting in various minor modifications to the case. In addition, the baud rate has been increased along the single channel and EMC performance has been improved.

Trusted Filter V1.2A.2

This version includes an update to the HFFN command table in the 1.2A.1 version of the Trusted Filter.

For further information on the scope of ACE for this product please contact AISEP at: [email protected].